It's what you and I might call a grind, someone who is overly assiduous in hitting the books.这是个你我都会称之为刻苦用功的学生，读书极其认真勤勉。Paul kept on the right side of his teachers by working really hard.保罗刻苦用功，深得老师喜爱。You have worked hard all year, and should be able to make light work of passing the examinations.你一年到头刻苦用功，一定能轻而易举地通过这次考试。